Machines for sharpening rotary cutters



July 21, 1964 Filed NOV. 15 1961 A. S. ROWLEY MACHINES FOR SHARPENING ROTARY CUTTERS 3 Sheets-Sheet 1 July 21, 1964 A. s. ROWLEY 3,141,266

MACHINES FOR SHARPENING-ROTARY CUTTERS Filed Nov. 15, 1961 s Sheets-Sheet 2 July 21, 1964 A. s. ROWLEY 3,141,266

MACHINES FOR SHARPENING ROTARY CUTTERS Filed Nov. 15, 1961 S Sheets-Sheet 3 Q) L 9 J \i\ l h J i J J 1 F l B. 5-

eon/5) United States Patent 3,141,266 MACHINES FOR SHARPENING ROTARY CUTTERS Alan Stamford Rowley, Grafton St., Pendleton, England Filed Nov. 15, 1961, Ser. No. 152,574 1 Claim. 01. 51-34) This invention relates to improvements in machines for grinding and sharpening the rotary cutting faces of the teeth of milling and similar cutters having integral cutting teeth, the machine being of the type in which the cutter to be ground and sharpened is mounted on an arbor carried in a frame supporting a grinding wheel, the arbor being automatically rotated one tooth after each grinding operation to bring a succeeding tooth into the grinding position.

The invention comprises a machine of the type referred to comprising crank mechanism for imparting a horizontal to and fro motion to the grinding wheel, and a single tooth pinion mechanism for automatically rotating the milling or like cutters one tooth after each grinding operation.

The invention will be described with reference to the accompanying drawings:

FIGURE 1 is a partially sectioned side elevation of a tool grinding machine according to a preferred embodiment of the present invention and illustrating a cutter mounted in position to be sharpened by the grinding wheel of the machine;

FIGURE 2 is a diagrammatic plan view of the drive gear train embodied in the machine illustrated in FIG- URE l for traversing the grinding wheel and for rotating the cutter to be sharpened;

FIGURE 3 is a vertical sectional view of the arbor illustrated in FIGURE 1 and of the drive train therefor;

FIGURE 4 is a sectional view taken substantially along the line 4-4 of FIGURE 3;

FIGURE 5 is a sectional plan view taken along the rotational axis of the grinding wheel and showing internal details of the grinding wheel head illustrated in FIG- URE 1;

FIGURE 6 is a detailed sectional view taken substantially along lines 66 of FIGURE 3; and

FIGURE 7 is a longitudinal sectional view taken along the rotational axis of the divided drive train shaft illustrated in FIGURE 2 for adjusting the grinding wheel cut applied to the cutter.

A rotary cutter A to be ground is mounted on a vertical arbor B journalled in the machine frame D. A grinding wheel C for sharpening the teeth of the cutter A is mounted on a slide 0 to be capable of movement towards and away from the grinding position of the cutter. The grinding wheel is continuously driven through bevel gearing (FIGURE 5) by a motor within housing C carried by slide c. The vertical arbor B is carried to rotate in a pedestal d mounted in the frame D, and is formed with a shoulder b to receive the cutter A. A spindle B provided with a head on its upper end passes through a central bore in the arbor B for locking the cutter thereon. The spindle may be formed in two parts coupled together by members h The lower end of the composite spindle B is threaded to receive a hand wheel B by which the position of the spindle is controlled.

The movement of the grinding wheel slide 0 and the registration of each tooth a of the cutter A in the grinding position is synchronised by mounting a main shaft 1 in the machine frame D actuated by a hand wheel 2 driving a pinion 30 mounted on the shaft 1 or by a motor 31 driving a further pinion 32 thereon through a chain. The hand wheel rotates independently of the motor through a free wheel drive and vice versa.

The shaft 1 carries an intermittent gear 3 such as a pinion having a single pinion 3a rotating a wheel 5 on a lay shaft 6 one tooth for each rotation of the main shaft. A lay shaft 6 is geared to a spindle 7 through change gears 8 which rotate the cutter arbor through bevel or other gearing 9.

A second shaft 11 is mounted in the frame D geared to the main shaft 1 by pinions 12. This second shaft 11 drives a crank pinion 13 through a chain 14 and sprockets 15 or otherwise. A connecting rod 16 fitted to this crank pin 3 imparts the to and fro transverse movement to the slide 0 on which the grinding wheel unit is mounted.

The gearing 8 between the lay shaft 6 and the arbor B may be varied to accommodate different numbers of teeth in the cutter A.

In order to vary or adjust the cut applied by the grinding wheel to the teeth the spindle intermittently rotating the arbor is formed in two parts 7 and 7 (FIGURE 7). A pinion a is mounted on or formed integrally on the spindle 7, the second spindle 7 being mounted in line with the spindle 7 and being journalled in a bushing a therein. A second pinion b is mounted on the second spindle 7 the pinions a b engaging respectively pinions 0 d carried on a stud d mounted to rotate with a worm wheel 18 keyed to the second spindle 7 within casing 17.

Worm wheel 18 is engaged by a worm 18 mounted in the frame on a worm shaft capable of rotation by a hand wheel 21 on a spindle carrying a pinion 22a meshed with a gear 22 mounted on the worm shaft. By rotating hand wheel 21 the relative angular positions of the two spindles 7 and 7 may be varied to thereby correspondingly vary the angular relationship of the cutter with respect to the path of movement of the grinding wheel.

The pinion a on the first spindle 7 may have 36 teeth and the pinion b on the second spindle 7 may have 32 teeth engaging respectively pinion c with 20 teeth and pinion d with 16 teeth. The pinion a 12 may be separated by a packing washer d In operation when the pinion a is intermittently rotated the drive is transmitted through c d the pinions to the pinion b which rotates the cutter being ground through the bevel gearing.

If, however, the pinion a is stationary and the worm wheel is rotated round it the pinion b will creep round the pinion a (at the rate of substantially one tooth per rev. of the worm wheel) thereby imparting a very small movement to the cutter arbor. By this means the cutter is rotated independently of the rotating drive and so given the required feed.

The angular positions of the two spindles 7, 7 is varied by the hand wheel 21.

In operation the cutter A to be ground is mounted on the arbor B and a tooth a on the cutter is sharpened by the grinding wheel C which is traversed on the slide along the face of the tooth a (on the in" stroke). By the end of the traverse (on the out" stroke) the single tooth pinion 3 has rotated one revolution and the tooth 3a thereon engaged the intermittent wheel 5 on the lay shaft 6 to rotate the cutter arbor B to bring a second tooth a on the cutter A into the grinding position. During the rotation of the arbor B the slide 0 carrying the grinding wheel C has been moved outwards by the connecting rod 16 to clear the crown of the tooth a and return to the grinding position for operation on the second tooth. The intermittent rotation of the arbor B and the to and fro movement of the slide 0 continues until all the teeth on the cutter A have been sharpened.

The indexing is thus automatic, much quicker and more accurate than in existing cutter sharpening apparatus and the machine may be operated by unskilled labour.

An electric suds pump may also be provided for lubrication purposes during the grinding operation.

I claim:

In apparatus for sharpening the cutting faces of a rotatable milling or like cutter, a stationary support, an arbor on which said cutter is adapted to be mounted and disposed for rotation about a fixed axis on said support, a slide member reciprocably mounted on said support for movement toward and from said arbor in a plane perpendicular to the axis of rotation of said cutter, a grinding wheel rotatably mounted on said slide member, motor means on said slide member for continuously rotating said grinding wheel, and synchronized means for intermittently rotating said arbor step by step in a selected direction and reciprocating said slide member into and out of grinding contact with successive faces of said cutter, said cutter being stationary at least during said contact and automatically indexed to position a new face in the path of said grinding wheel during the period that the grinding wheel is out of contact with said cutter, and means in References Cited in the file of this patent UNITED STATES PATENTS 1,817,405 Brarch Aug. 4, 1931 1,875,163 Schorff Aug. 30, 1932 2,136,266 Reinecker Mar. 8, 1938 2,836,014 Calderwood May 27, 1958 2,998,678

Belock et a1 Sept. 5, 1961 

